Consider adding a description field to the attribute schema

[mrshll1001]

attribute currently does not have a description property, which some people on the forum have highlighted may be desirable.

Attributes with taxonomy terms have access to the attribute.taxonomy_term.description field, but in cases where attributes are not adding a taxonomy term then all a data user / system has to go off of is attribute.value which could be meaningless without context.

Adding attribuite.description would address this lack, at least in the medium-term without a restructuring of HSDS' data model.

[mrshll1001]

@devinbalkind @Cskyleryoung I've added this as emergent based on your comments on https://forum.openreferral.org/t/we-need-a-normalized-url-table-in-the-pattern-of-the-phone-table/431/1